The rapidly evolving field of bioengineering has created a demand for a diverse library of different types of polymers offering a wide variety of choice of physical and mechanical properties. It is desirable that libraries of many different materials be available so that the specific polymer properties can be optimally matched with the requirements of the specific applications under development.
Examples of polymers suitable for various bioengineering applications include those described in U.S. Pat. Nos. 5,099,060; 5,665,831; 5,916,998 and 6,475,477, along with the polymers described in U.S. Patent Publication Nos. 2006/0024266 and 2006/0034769. There are numerous applications in which it is considered desirable for an implanted medical device to maintain its integrity and performance characteristics for extended periods of time, even under demanding mechanical conditions such as repeated mechanical flexure. Although many types of bioresorbable and/or biodegradable polymers are known, they are generally not selected for such applications because they were designed for temporary presence in the body and therefore lacked the desired combination of physical and mechanical properties. In addition, bioresorption and/or biodegradation tend to alter mechanical properties in unpredictable ways that are not necessarily linearly related to each other. Thus, there is a need for biocompatible, bioresorbable and/or biodegradable polymers having desirable mechanical properties, such as fracture and/or fatigue toughness, that have previously not been a primary design criteria for such polymers.